NOAA APT Satellites

The NOAA weather satellites are some of the easiest satellites to receive. For an excellent article see RTL-SDR Tutorial: Receiving NOAA Weather Satellite Images.

The NOAA satellites and APT frequencies are:

Satellite Frequency 
NOAA 15 137.6200 MHz
NOAA 18 137.9125 MHz
NOAA 19 137.1000 MHz


The recommended steps are:

  1. Install WXtoImg
  2. Install a virtual audio cable (VAC), either VB-Audio or Virtual Audio Cable
    • Select this device in the console (Receive DSP pane) and
    • WXtoImg recording Options
  3. In the satellite tracking window select a NOAA satellite (see the table above),
    • Add to the satellite list
    • Define the RX frequency with the Organise option
  4. in the Passes window press Current to display the passes for the currently selected satellite

An example of a APT frequency definition is shown below, note the mode is WFM (wide FM) which must be used here, the recommended bandwidth is 40 kHz:

When applied to the console the Receive DSP pane shows the values below, make sure:

  • Mode is WFM (wide FM)
  • Virtual Audio Cable (VAC) is selected
  • Volume level is 100
  • Filter with is 40 kHz
  • Squelch is Off
  • Notch filter is off


WXToImg Settings

The essential WXtoImg steps are shown below.

Kepler Data Update

From the File menu select Update Keplers - this loads the latest data from the sites configures in WXtoImg, this is usually

Recording Options

From the Options menu select Recording Options. Here you must select the same virtual audio cable configured in the SDR Console, in this example Line 1 (Virtual Audio Cable). The name depends on the VAC program you have installed. You must select the same device in the Receive DSP pane of the console.


From the File menu select Record, select Record and auto process then press Auto Record.

 Do this every time you start WxToImg.


APT Signal And Image

When you are receiving a signal the display in the console will be similar to the image below, recommended settings are:

  • Mode WFM (wide FM)
  • Virtual Audio Cable (VAC) selected
  • Volume level is 100
  • Filter with 40 kHz
  • Squelch Off
  • Notch filter off

Assuming you are piping the audio via a VAC to WXtoImg your resulting image will be something like this once the recording has finished and WXtoImg has processed the data:

Yes - it's that simple!


For general-purpose satellite reception a log periodic from WIMO is used, see model FULL. Here are a couple of photos, the rotator is an alfaSPID with Green Heron controller, the masthead pre-amp from SSB Electronics is the LNA 5000.